(Credit: Dr. Brett Savoie – Caltech/Perdue)
Usable form of energy is converted into work but unfortunately reversing the process of work to get completely back the original usable energy is not possible.
On the contrary, demand for energy will be ever increasing as the global population expands. The increase in the global rate of consumption of energy in the last 10-year average of 1.7% per year, will keep increasing forever. Therefore, production of energy, its maximum usage and storage are equally important for the growth and sustenance of civilization. To cope with the energy demands of the ever-increasing global population, it is necessary to double the present rate of energy production of 14 TW by 2050 (2, 3) (Fig. 1).
With the changing lifestyles of an increasing number of inhabitants, our energy rate demand will double from 14 TW (2010) to 28 TW (2050). TOE = ton of oil equivalent. Map: © Macmillan Mexico/Haide Ortiz Ortiz, Mario Enrique Ramí rez Ruiz.
Energy is produced from both non-renewable (oil, natural gas, coal, nuclear etc.) and renewable (wind, solar, tidal, biomass and geothermal) resources to date (4, 1) (Fig 2. and Fig. 3). However, due to the devastating effect of the carbon footprint and consequently climate change, it has been absolutely imperative to switching to renewables as soon as possible. This switching is a must in order to reduce greenhouse gas emissions to net zero or even negative by mid-century irrespective of availability/non-availability of non-renewable sources.
In order to achieve this goal, the production and distribution of energy from renewable sources though riding, but not becoming smooth for a rapid take off. The fundamental limitations for a smooth transition in favour of renewable energy sources are as follows: (a) cost of the production and scaling of renewables is not competitive with the non-renewables (b) renewable resources are weather dependent and therefore inherently intermittent (resources are not available 24X7, e.g.; sunlight is not available at night, all the time may not be equally windy, droughts may occur in some season) and generally dispersed in comparison to the centralized nonrenewable power stations that currently supply the vast majority of electrical energy. Integration of the renewable sources to the existing nonrenewable traditional transmission and distribution grid has not been possible. Therefore, the building of new DER (Distributed Energy Resources) system or DESS (distributed energy storage system) for renewable sources though has many new advantages but add to the cost at the initial stage for the distribution of the generated energy.
Fig. (2): Sources: World historical oil, natural gas, and coal consumption from 1950 to 1964 is estimated from carbon dioxide emissions (Boden, Marland, and Andres 2017); world primary energy consumption and its composition from 1965 to 2016 is from BP (2017); world primary energy consumption and its composition from 2017 to 2050 is based on this report’s projections.
The solution to the variable output of renewables has been envisaged through the development of efficient storage technologies. Hence, complete shifting to renewables, therefore, demands significant development in large scale but a low cost of an energy storage system (ESS) balancing between supply and demand. The process should include conversion and storage of electrical energy from a source to another form of energy when demand is low and again conversion of the stored form of energy to electrical form when demand is high. Unfortunately, currently, only around 1% of the energy consumed worldwide have the capacity to be stored (5). Several techniques (mechanical chemical, electrical, electrochemical, thermal, magnetic, potential, kinetics etc.) have been developed to date and every system possesses merits and demerits. However, Electrochemical Energy Storage System (ESS), otherwise known as the Battery Energy Storage System (BESS), is far ahead in the race than others due to its attainable high efficient and flexible performances, and in its versatilities in its form and volume.
Fig. (3): BP Statistical Review of World Energy, 67th Ed.
Fig. (3): BP Statistical Review of World Energy, 67th Ed.
The four major categories of rechargeable batteries being used in different applications today are Lead acid, Alkaline (Nickel), Silver and Lithium batteries. But the market is largely dominated by the Lithium-ion batteries due to its superior energy density (6). But there are two key concerns regarding Lithium batteries: (1) These batteries are hugely costly (2) and limited availability of lithium resources as mineral on the earth is not coping to the world’s demand and its extraction process from the crude is very expensive. Therefore, alternative chemistry supporting affordable, high energy density and environment-friendly battery technology is the need of the hour to develop.
Now in a recent study, chemists from several institutions, including Caltech, Honda Research Institute and Lawrence Berkeley National Laboratory, USA, have shown a new method of making rechargeable batteries based on fluoride, the negatively charged form (anion) of the element fluorine (7). In this technological new development, fluoride anion has been made able to shuttle between electrodes using a liquid electrolyte called bis(2,2,2-trifluoroethyl)ether (BTFE) at room temperature. BTFE help stabilizes the fluoride anion so that it can shuttle electrons back and forth between two electrodes in the battery. It is expected that this newly developed battery technology may have eight to ten times higher energy density than Lithium Battery (4).
1) BP statistical Review of World Energy, 67th Ed., June 2018
2) Lewis, N. (2007) Powering the planet. MRS Bulletin 32, 808–820.
3) International Energy Agency Key World Energy Statistics 2011 (http://www.iea.org/publications/freepublications/publication/)
4) http://peakoilbarrel.com/world-energy-2017-2050-annual-report/ (a guest post by: Dr. Minqi Li, Professor, Department of Economics, University of Utah)
5) Larcher D., Tarascon J.M. (2015) Towards greener and more sustainable batteries for electrical energy storage. Nat. Chem. 7(1):19-29.
6) K. Mizushima, P. C. Jones, P. J. Wiseman and J. B. Goodenough (1980) LixCoO2 (0<x<-1): A new cathode material for batteries of high energy density. Mater. Res. Bull., 15 (6), 783–789.
7) Davis V.K., Bates C.M., Omichi K., Savoie B.M., Momčilović N., Xu Q., Wolf W.J., Webb M.A., Billings K.J., Chou N.H., Alayoglu S., McKenney R.K., Darolles I.M., Nair N.G., Hightower A., Rosenberg D., Ahmed M., Brooks C.J., Miller T.F. 3, Grubbs R.H., Jones S.C. (2018) Room-temperature cycling of metal fluoride electrodes: Liquid electrolytes for high-energy fluoride ion cells. Science 362 (6419), 1144-1148.
Dr. Susanta Pahari, PhD, is a Professor of Biochemistry at Skyline University Nigeria. He has a PhD. in Biochemistry from the University of Calcutta, India.
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